This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Annual or perennial rather fleshy, usually glabrous leafy herbs, with erect, simple or branched, striate or grooved stems. Leaves alternate, petioled, hastate or deltoid, with oblique, cylindric or funnelform ocreae. Flowers small, white or green, in terminal or axillary usually paniculate racemes, perfect, borne solitary or several together from each ocreola, slender-pedicelled. Calyx about equally 5-parted, persistent and unchanged in fruit, the segments petaloid, shorter than the achene. Stamens 8, included; filaments filiform, glabrous; anthers oblong. Ovary 1-celled, 1-ovuled; style 3-parted: stigmas capitate. Achene 3-angled. Embryo central, curved, dividing the mealy endosperm into two parts; cotyledons broad. [Greek, beech-wheat, from the similarity of the grain.]
About 6 species, natives of Europe and Asia. Type species: Fagopyrum tataricum Gaertn.
Racemes panicled or corymbose; angles of the achene not crested.
Racemes mostly simple; angles of the achene crested, undulate.
Polygonum Fagopyrum L. Sp. PI. 364. 1753. Fagopyrum esculentum Moench, Meth. 290. 1794. F. Fagopyrum Karst. Deutsch. Fl. 522. 1880-83.
Annual, glabrous except at the nodes, stem strongly grooved when old, 1°-3° high. Leaves hastate, i'-3,' long, abruptly narrowed above the middle, acuminate, the nerves on the lower surface slightly scurfy; ocreae brittle and fugacious; racemes mostly panicled, sometimes corymbose, many-flowered, erect or inclined to droop; pedicels as long as the calyx; segments white or whitish; stamens included; style-branches deflexed in fruit; achene acute, 2 1/2" long, about twice as long as the calyx, its faces pinnately-striate when mature, the angles acute, entire.
In waste places, and persistent in fields after cultivation. Reported from almost all parts of the northern United States and southern British America. Also in the West Indies. Native of eastern Europe or western Asia. Brank. Corn-heath. Beech-wheat. Crap. Saracen's-corn or -wheat. June-Sept.
Polygonum tataricum L. Sp. PI. 364. 1753.
Fagopyrum tataricum Gaertn. Fr. & Sem. 2: 18.-2. pi. 189. f. 6. 1791.
Annual, similar to the preceding species, but the leaves deltoid-hastate or oblong-hastate, often broader than long, 1'-4' wide, acute or short-acuminate at the apex; racemes terminal and axillary, mostly solitary, simple and few-flowered, long-peduncled; flowers whitish, short-pedicelled; achene subacute, 21/2" long, its angles crested with 3 prominent lobes above the middle, its faces pinnately sulcate from a conspicuous groove.
In waste places, eastern Canada and New England. Rough buckwheat. Adventive from Asia. Summer.